70 research outputs found

    Application de la tomographie sonique au diagnostic du béton

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    Recognition of the many problems in concrete structures requires the reconstruction of their internal image. For this reason, some years ago, a new nondestructive method, sonic tomography, has been developed for scanning concrete structures. This method is most often based on transient stress wave propagation for verifying a concrete body, as well as measuring the wave velocity. The relative variation in wave propagation velocity in the material provides information about changes in the structure, and therefore the state of degradation. Capacity and limitation of this method for reconstructing the internal image of the concrete structures are addressed in this thesis. This study discusses some experiments in which sonic tomography were performed on various concrete models in laboratory and the structures in service in-situ. In this case, two important aims are the main focus: (1) Degraded area is usually marked by fracture and delaminations or poorly performed sections within the structure. Unfortunately, most of the degradation in concrete structures remain undetectable to the naked eye. Sonic tomography is a strong technique to show the damaged areas in body concrete. In addition, this technique is able to evaluate internal reparation (e.g. control of grout-injection zones). (2) This is limited by the measurement and reconstruction of image conditions and their parameters (frequency, pixels size, rays type, measurement step,...). For illustrating the real image it is necessary to know precisely these conditions and the quality of their influence on the tomographic image

    Antibiotic prescription for endodontic treatment: General dentist knowledge + practice in Shiraz

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    INTRODUCTION: Diseases of the dental pulp and periapical tissues are chiefly caused by microorganisms. Antibiotics are used in some endodontic cases; however, successful cases can predominantly be achieved by mechanical and chemical cleaning of the canal or surgical intervention.MATERIALS & METHODS: The aim of this study was to determine the knowledge of General Dental Practitioners (GDPs) in Shiraz in respect to antibiotic prescriptions during and after endodontic treatment. A one-page questionnaire was sent to 200 active general dentists. Of the 120 surveys returned, 93 were accepted. The data were analyzed using t-test, Chi-square, ANOVA and Fisher’s Exact Test. RESULTS: Only 29% of dentists had full knowledge (correct answers to all questions) of antibiotic prescription protocols in pulpal and periapical disease. Amoxicillin 500 mg capsule was the drug of choice of dentists. Total of 42% of GDPs had full knowledge of antibiotic prescription protocols for persistent or systemic infections cases. GDPs more recently qualified had slightly greater knowledge compared to GDPs with experience; however, this difference was not significant. Also, there was no significant difference between genders. CONCLUSION: General practitioners’ knowledge about antibiotics seems inadequate and further education is recommended to update the practitioners

    Compréhension de la rétrodiffusion des micro-ondes sur le sol nu en utilisant l'inversion des paramètres de surface, les réseaux de neurones et l'algorithme génétique

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    Estimates of the physical parameters of the soil surface, namely moisture content and surface roughness, are important for hydrological and agricultural studies, as they appear to be the two major parameters for runoff forecasting in an agricultural watershed. Radar has high potentiality for the remote measurement of soil surface parameters. In particular, the investigation of the radar backscattering response of bare soil surfaces is an important issue in remote sensing because of its capacity for retrieving the desired physical parameters of the surface. The objective of this study is to formulate and to constrain a methodology for solving the inverse problem for the operational retrieval of soil surface roughness and moisture. To separate the effects of the different parameters on the measured signal over complex areas, multi-technique concepts (multi-polarization, multi-angular, multi-sensor, multi-frequency, and multi-temporal) are the main solution. In this work, based on a simulation study, three different configurations, multi-polarization, multi-frequency and multi-angular, are compared to obtain the best configuration for estimating surface parameters and the multi-angular configuration gives the best results. Based on these results, this study was continued according to five different phases: (1) A new index, the NBRI (Normalized radar Backscatter soil Roughness Index), using the multi-angular approach was presented. This index can estimate and classify surface roughness in agricultural fields using two radar images with different incidence angles. (2) A new linear empirical model to estimate soil surface moisture using RADARSAT-1 data was proposed. This model can provide soil moisture with reduced errors of estimation compared to other linear models. (3) Inversion of the surface parameters using nonlinear classical methods. In this case, the Newton-Raphson method, an iterative numerical method, was used in the retrieval algorithm to solve the inverse problem. (4) In this phase, the neural network technique, with a dynamic learning method, was applied to invert the soil surface parameters from the radar data. The results were obtained through performance testing on two different input schemes (one and two data series) and two different databases (theoretical and empirical). The advantage of the multi-angular set with measured data is apparent. These results are the best in this study. (5) Finally, a novel genetic algorithm (GA) was developed to retrieve soil surface parameters. In this study, it is shown that the genetic algorithms, as an optimization technique, can estimate simultaneously soil moisture and surface roughness from only one radar image

    Modeling IoT enablers for humanitarian supply chains coordination

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    Disaster relief operations rely on reliable real-time information sharing during disasters to coordinate scarce resources and save lives. The Internet of Things (IoT) has recently been regarded as an important technology for enhancing information sharing in disaster response operations to achieve effective coordination, accurate situational awareness, and comprehensive visibility of operational resources. Despite its relevance, its adaptation and implementation have been fraught with complexity. This research aims to understand the IoT enablers of humanitarian supply chain coordination. Seven dimensional enablers have been formulated by reviewing the literature and validating with practitioners’ opinions. A structural model is then developed using the Decision-Making Trial and Evaluation Laboratory (DEMATEL) technique that addresses the interdependencies of IoT enablers in humanitarian supply chain coordination. Finding provides insights into the interplay between management support, IT infrastructures, and third-party logistics service providers as key enablers towards adaptation and implementation of IoT in humanitarian supply chains. Results provide important implications and insight to decision-makers in international humanitarian organizations toward adaptation and implementation of IoT systems in humanitarian supply chains

    Chromium removal and water recycling from electroplating wastewater through direct osmosis: Modeling and optimization by response surface methodology

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    Background: Considering the carcinogenic effects of heavy metals, such as chromium, it is essential to remove these elements from water and wastewater. Direct osmosis is a new membrane technology, which can be a proper alternative to conventional chromium removal processes. Methods: The wastewater samples were collected from an electroplating unit, located in Alborz industrial city, Qazvin, Iran. Magnesium chloride was used as the draw solution, and a semipermeable membrane (Aquaporin) was used in this study. The experiments were designed, using response surface methodology (RSM) and central composite design (CCD) with draw solution concentration (0.5- 1.5 M), feed solution concentration (4-12 mg/L), and experiment time (30-90 minutes) as variable factors. The chromium concentration and water flux were also measured, based on atomic absorption spectrophotometry and water flux equation, respectively. Results: Direct osmosis was highly efficient in chromium removal and water recycling. Water flux and chromium removal efficiency were 15.6 LMH and 85.58%, respectively, under optimal conditions (draw solution = 1.27 mol/L, feed solution = 4 mg/L, and experiment time = 90 min). In terms of validity, the results predicted by the quadratic polynomial model were in good agreement with the responses reported in the laboratory. Conclusion: In direct osmosis, the use of magnesium chloride as the draw solution resulted in the acceptable chromium removal from electroplating wastewater. Using this method, chromium concentration in wastewater reduced to a level lower than the discharge standards, established by Iran’s Department of Environment. Keywords: Direct osmosis, Chromium removal, Electroplating, Optimizatio

    WDR7 up-regulation upon knocking down of neighboring non-coding RNA using siRNAs encapsulated in polyamidoamine dendrimers

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    Objective(s): Breast cancer is the second leading cause of cancer death in females. Understanding molecular mechanisms in cancer cells compared with normal cells is crucial for diagnostic and therapeutic strategies. Long intergenic non-protein coding RNA, a regulator of reprogramming (lincRNA-RoR) is a noncoding RNA which initially was detected in induced pluripotent stem cells, and it has an important role in cell reprogramming and highly expressed in breast cancer cells. A key point in successful gene silencing is the usage of siRNA delivery system that is safe and efficient. Materials and Methods: In this study, the fifth-generation of PAMAM dendrimer is used as a nanocarrier for entering siRNA molecules for gene silencing of lincRNA-RoR. WDR7 is the gene encoding adjacent of lincRNA-RoR, which has an important role in apoptosis and cell cycle. Gel retardation assay was used to find the best Negative/Positive (N/P) molar charge ratio of siRNA-PAMAM transfected into MDA-MB 231 cells. MTT assay was performed 24 hr after transfection revealed the IC50 value (half maximal inhibitory concentrations) about 100 nanomolar for lincRNA-ROR siRNA. Results: The lincRNA-RoR and WDR7 gene expression changes were evaluated by real-time PCR after siRNA treatment and showed an increase in the gene expression of WDR7. Conclusion: This study showed that PAMAM dendrimer G5/siRNA could be a useful system delivery for future gene therapy approaches. Keywords Author Keywords:Breast cancer; lncRNA ROR; Polyamidoamine dendrimer (PAMAM); Transfection; WDR7 KeyWords Plus:CANCER STEM-CELLS; LINC-ROR; RESISTANCE; GENE; EXPRESSION; PROMOTES; INVASION; SPONG

    A Hidden‎ Markov Model‎ ‎Based‎ ‎Extended Case-Based Reasoning Algorithm for Relief Materials Demand Forecasting

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    ‎In emergency situations‎, ‎accurate demand forecasting for relief materials such as food‎, ‎water‎, ‎and medicine is crucial for effective disaster response‎. ‎This research is presented a novel algorithm to demand forecasting for relief materials using extended Case-Based Reasoning (CBR) with the best-worst method (BWM) and Hidden Markov Models (HMMs)‎. ‎The proposed algorithm involves training an HMM on historical data to obtain a set of state sequences representing the temporal fluctuations in demand for different relief materials‎. ‎When a new disaster occurs‎, ‎the algorithm first determines the current state sequence using the available data and searches the case library for past disasters with similar state sequences‎. ‎The effectiveness of the proposed algorithm is demonstrated through experiments on real-world disaster data of Iran‎. ‎Based on the results‎, ‎the forecasting error index for four relief materials is less than 10\%; therefore‎, ‎the proposed CBR-BWM-HMM is a strong and robust algorithm‎

    Lipid-modifying effect of vitamin D fortified products: A systematic review and meta-analysis of Randomized Controlled Trials

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    Objectives: Various fortification strategies have been proposed to account to treat or prevent vitamin D deficiency. However, the optimum fortification approach, and the effect of these on health is not widely understood. There have been controversial reports regarding the effect of vitamin D fortification on the lipid profile. The aim of present review is the evaluation of administration of vitamin D fortified products on lipid profile.Methods: We used databases including PubMed/Medline, ISI Web of Knowledge, Science Direct, Scopus and Cochrane Library. A search was conducted until 2020 Randomized controlled trials that have assessed the relationship between consumption of vitamin D fortified products and serum lipid profile were included. The relationship between fortification dose, dairy or non-dairy fortification as well as duration of intervention and plasma lipid profiles evaluated in separate sub-groups.Results: Among serum lipids including total cholesterol(TC), triglyceride(TG), low density lipoprotein(LDL) and high density lipoprotein(HDL), fortification of vitamin D was reported to have a significant effect on reducing total cholesterol (pooled estimate: -0.089 mmol/L, 95%CI: -0.134 to -0.044, p<0.001). Its effect on other lipid profiles were not significant (LDL pooled estimate:-0.115 mmol/L, 95%CI:-0.238 to 0.008; HDL pooled estimate:0.024 mmol/L, 95%CI:-0.024 to 0.071; TG pooled estimate:-0.176mmol/L, 95%CI:-0.499 to 0.148).Conclusion: This meta-analysis demonstrated that vitamin D fortification could significantly reduce TC both in long and short term interventions and in different products. However this reduction, whilst statistically significant, may not be clinically important. The effect of fortification on other lipid profile components vary depending on dose and duration
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